All online calculators
Browse practical tools for loans, percentages, currency, calories, tiles, laminate, age and business days.
Thin lens calculator
Image distance, magnification and image type from the thin lens equation.
Time dilation calculator
Lorentz factor, time dilation and length contraction.
Weekly timesheet calculator
Weekly hours from start, end and break per shift, with overtime and gross pay.
Air pressure at altitude calculator
Atmospheric pressure, temperature and air density at a given altitude.
Dripping tap water loss calculator
How much water and money a dripping tap wastes per day, month and year.
Quarter mile time calculator
Quarter mile elapsed time and trap speed from engine power and vehicle mass.
Ratio calculator
Simplify a ratio and divide an amount in proportion.
Sealant volume calculator
Sealant needed for a joint of a given section, and how many cartridges that is.
Wind power calculator
Power in the wind and the power a rotor can extract, against the Betz limit.
Carnot efficiency calculator
The ceiling efficiency of a heat engine from two temperatures.
Power and root calculator
Powers and roots within the supported real domain.
Yeast converter
Convert between fresh compressed, active dry and instant yeast by weight.
Coaxial cable impedance calculator
Characteristic impedance of coax from the conductor and shield diameters and the dielectric.
Cube calculator
Volume, surface area and diagonals of a cube from its edge, volume or surface area.
Home equity loan calculator
Amount available against a home, allowing for the outstanding mortgage and the loan-to-value limit.
Mach number calculator
Mach number from speed and air temperature, with the flight regime named.
Pyramid frustum calculator
Volume, slant height and surfaces of a square pyramid frustum.
Terminal velocity calculator
Terminal velocity in air with the time and distance needed to reach it.
TV viewing distance calculator
Geometric distances for 40°/30° screen angles and an assumed 1′ pixel.
Bernoulli equation calculator
Pressure at the second section of a flow from speeds and heights, with the total head.
Pipe weight calculator
Pipe mass from outside diameter, wall thickness, length and material density.
Rhombus calculator
Area, side, perimeter and height of a rhombus from its two diagonals.
System of linear equations calculator
Solves a system of two linear equations in two unknowns by Cramer’s rule.
Annulus calculator
Area of the ring between two circles, its width and both circumferences.
APR and APY calculator
Conversion between the nominal and the effective annual rate.
COGS calculator
Cost of goods sold from opening inventory, purchases and closing stock.
Early loan repayment calculator
Interest saved and term shortened by a regular extra payment.
Fluid estimate calculator
Educational fluid estimate from explicit weight, activity and heat assumptions, not a drinking requirement.
Profit, margin and markup calculator
Profit, margin and markup from revenue and costs.
Acceleration calculator
Acceleration from a change in velocity over time, or final velocity from acceleration.
Ad budget funnel calculator
Clicks, orders, revenue and ROAS from a budget and a conversion rate.
Audience growth calculator
Total audience growth and the average rate for one period.
Bonus calculator
Bonus before and after tax from salary, percentage and tax rate.
CPA, CPL and CPI calculator
Cost per action, lead or install from the budget and the number of actions.
CPC calculator
Cost per click from budget and clicks, plus CPM and click-through rate.
Ellipse calculator
Area, approximate perimeter, eccentricity and foci of an ellipse from its semi-axes.
Emergency fund calculator
Fund target in months of expenses, and progress towards it.
Employee cost calculator
Full cost of an employee including contributions and overhead.
Overtime pay calculator
Monthly pay with overtime hours and the effective hourly rate.
Salary period converter
Convert a salary between hourly, daily, monthly and yearly.
Salary raise calculator
Raise percentage from a new salary, or the new salary from a percentage.
Unit cost calculator
Cost of a single produced unit from materials, labour and overhead.
VO2 max calculator
Two empirical VO₂max estimates from existing Cooper or pulse data, with applicability limits.
Battery series and parallel calculator
Pack voltage, capacity and energy from the wiring arrangement.
Car depreciation calculator
Residual value of a car after several years of ownership.
Centripetal force calculator
Centripetal force, acceleration, angular velocity and period of revolution.
Conical frustum calculator
Volume, slant height and surfaces of a truncated cone from two radii and the height.
CSS units converter
Convert px, rem, em, pt and the other CSS length units.
Dice probability calculator
Probability of rolling a given sum on several identical dice.
Email marketing metrics calculator
Delivery, open and click rates for an email campaign.
Gravitational force calculator
Attraction between two bodies from the law of universal gravitation.
Leverage calculator
Position size, liquidation price and the distance to it.
Prism calculator
Volume and surface areas of a regular prism from base side and height.
Pyramid calculator
Volume, slant height and surface areas of a regular pyramid.
Rafter length calculator
Rafter length, roof angle and slope for a gable roof.
Rounding calculator
Round to a chosen number of decimal places, to the nearest, down or up.
Single-phase power calculator
Active, apparent and reactive power of a single-phase circuit, or current from power.
Sleep time calculator
Wake-up time or bedtime using assumed 90-minute blocks.
Slope calculator
Slope in per cent and degrees from rise and run.
Vacation accrual calculator
Leave balance from the annual entitlement, months worked and days taken.
Wavelength and frequency calculator
Relates wave speed, frequency and wavelength in any direction.
Aquarium water change calculator
Volume of water to prepare for a change, corrected for substrate and decor.
ARPU and ARPPU calculator
Average revenue per user and per paying user, plus the paying share.
Modular scale calculator
Typographic sizes from a base and a ratio, with a table of steps.
Pet age calculator
Illustrative human-age estimate for a cat or dog using the 15/9/4/7 scale.
Pet food calculator
Daily food ration from body weight, requirement multiplier and food energy.
Churn and retention calculator
Churn, retention, net growth and average customer lifetime for a period.
Conversion rate calculator
Share of visits with a target action and cost per converting visit.
MRR and ARR calculator
Current monthly recurring revenue, its annualized rate and a next-month MRR change scenario.
Fuel economy converter
Convert fuel economy between L/100 km, km/L and miles per gallon.
Maximum loan amount calculator
The largest loan your income supports at a given debt burden, rate and term.
Time value of money calculator
Future value of a sum, and discounting future money back to today.
Inflation calculator
Purchasing power of a sum after several years, and how much is lost.